Evaporation-controlling container inserts

ABSTRACT

An apparatus configured for mixing the contents of one or more fluid containers includes a fluid container support platform configured to hold one or more fluid containers. The fluid container support platform is configured to index the container to one or more specified locations and to be moved in an orbital path about an orbital center independently of the rotation about the central axis of rotation. The apparatus further includes an indexing drive system configured to effect indexing movement of the container support platform and a vortex drive system configured to effect powered orbital movement of the container support platform about the orbital center. An evaporation limiting insert placed within containers reduces exposure of the fluid contents of the container to atmospheric air, thereby reducing susceptibility of the fluid contents to evaporation.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation claiming the benefit under 35 U.S.C.§ 120 of the filing date of non-provisional patent application Ser. No.14/211,668 filed Mar. 14, 2014, which claims the benefit under 35 U.S.C.§ 119(e) of the filing date of U.S. Provisional Application No.61/783,670, filed Mar. 14, 2013, each of which is incorporated herein byreference.

FIELD

This disclosure is directed to a fluid container mixing apparatusconfigured to carry and agitate a plurality of fluid containers and, inparticular, is directed to an apparatus configured to independently movethe containers to selectively present any of the containers in aspecified location or oscillate the containers in a vortexing motion toagitate the containers and mix the contents thereof.

BACKGROUND

Automated processes, such as chemical, biological, or industrialprocesses, often involve the use, processing, and/or manipulation offluid solutions and/or fluid suspensions. Typically, such fluidsolutions and suspensions are contained in a plurality of containers,often of various sizes, that must be made accessible to modules of amulti-module instrument for performing such automated processes. Inaddition, it is often necessary for an operator to provide new, fullcontainers to such an instrument and to remove used, empty containersfrom the instrument. Thus, it is often necessary in such automatedprocesses to move multiple containers of various sizes to differentpositions that are accessible to different modules, and/or it isnecessary to move different bottles, one-at-a-time, to a single locationthat is accessible to a particular module.

For example, in a processing instrument that includes a robotic pipettorfor aspirating fluids from and/or dispensing fluids into containers,there may be a single location at which fluid containers are accessibleto the pipettor, either due to limitations in the movement of thepipettor or due to the fact that other locations are occupied by othermodules. It may also be necessary to move bottles from a position atwhich an operator provides bottles to the instrument to a positionwithin the instrument or to move empty bottles from a position withinthe instrument to a position where the empty containers can be removedby the operator. Thus, an apparatus is required to move fluid containersfrom one location within the instrument to one or more other locationswithin the instrument.

Furthermore, fluid solutions or suspensions must be mixed to maintainthe solute in solution or to maintain material, e.g., solid orsemi-solid particles, in suspension. Mixing is often effected byagitating the container to mix the fluid solution or fluid suspensioncontents of the container. Thus, an apparatus is required to agitate thefluid containers. The frequency of mixing required will depend on thenature of the solution or suspension; some solutions or suspensions willrequire only infrequent mixing while other solutions or suspensions willrequire constant or nearly constant mixing.

For example, in many nucleic acid diagnostic tests, in which a goal ofthe test is to identify the presence and/or amount of a nucleic acid ofinterest, it is well known to use a probe that will hybridize to thenucleic acid of interest and emit, under specified conditions, adetectable signal so as to indicate the presence or, depending on thestrength of the signal, the amount of the target nucleic acid that ispresent in a sample.

Before or after exposing the target nucleic acid to a probe, in certainassays the target nucleic acid can be immobilized by target-capturemeans, either directly or indirectly, using a “capture probe” bound to asubstrate, such as a magnetic bead, or particle. When magnetic beadscomprise capture probes, magnets in close proximity to the reactionvessel are used to draw and hold the magnetic beads within a specifiedarea in the vessel, or in a fluid transfer apparatus.

Such target capture probes are provided in the form of fluid suspension.A robotic pipettor aspirates a specified amount of the probe from acontainer positioned in a location that is accessible to the pipettorand the probe is transported to and dispensed into a receptacle vesselthat contains, or will contain, other process materials, includingsample material. At times during which the pipettor need not access thecontainer, the container should be agitated to maintain the magneticparticles of the probe in suspension if additional aliquots of the fluidsuspension are required.

In an instrument for performing automated processes that includesmultiple processing modules, it is typically desirable that theinstrument occupy as compact a space as possible, and it isindispensable that the various modules be configured and arranged tooperate without interfering with each other. Due to space limitations,therefore, it may not be practical to accommodate separate apparatusesfor moving and agitating fluid containers. Moreover, if frequentagitation of a container is required to maintain the fluid in solutionor suspension, it may be impractical to move containers back and forthbetween apparatuses for moving the container and agitating thecontainer. Thus, an ideal fluid handling module for an instrument forperforming automated processes supports the combined functionalities ofmoving containers to one or more specified locations within theinstrument and agitating the containers in a compact and space-efficientplatform.

SUMMARY

Aspects of the present disclosure are embodied in a fluid containermixing apparatus comprising a container support platform, an indexingdrive system, and a vortex drive system. The container support platformis configured to hold one or more fluid containers and is constructedand arranged to be movable in such a manner to index the fluidcontainers to sequentially place each of the containers in one or morepredetermined positions, and the container support platform isconfigured to be movable in an orbital path about an orbital center. Theindexing drive system is configured to effect powered indexing movementof the container support platform. The vortex drive system is configuredto effect powered movement of the container support platform in theorbital path.

According to other aspects of the disclosure, the container supportplatform is constructed and arranged to index the fluid containers byrotating about an axis of rotation.

According to other aspects of the disclosure, the indexing drive systemis configured to effect powered rotation of the container supportplatform.

According to other aspects of the disclosure, the indexing drive systemand the vortex drive system are configured to be operable independentlyof each other.

According to other aspects of the disclosure, the indexing drive systemand the vortex drive system are configured to be selectively operatedsimultaneously.

According to other aspects of the disclosure, the indexing drive systemcomprises a indexing drive motor having a rotating output shaftoperatively coupled to the container support platform to convert poweredrotation of the output shaft into rotation of the container supportplatform.

According to other aspects of the disclosure, the indexing drive motoris operatively coupled to the container support platform by a driveshaftwheel mounted to the output shaft, an indexing drive pulley coupled tothe container support platform, and a drive belt trained about thedriveshaft wheel and the indexing drive pulley.

According to other aspects of the disclosure, the indexing drive motoris operatively coupled to the container support platform by a driveshaftgear rotated by the output shaft and an indexing drive gear coupled tothe container support platform, wherein the driveshaft gear isoperatively engaged with the indexing drive gear.

According to other aspects of the disclosure, the vortex drive systemcomprises a vortex drive motor having an output shaft and a vortextransmission. The vortex transmission is coupled to the vortex drivemotor and to the container support platform and is constructed andarranged to convert powered rotation of the output shaft of the vortexdrive motor into orbital movement of the container support platform.

According to other aspects of the disclosure, the fluid container mixingapparatus further comprises a driveshaft wheel coupled to the vortexdrive motor and a vortex drive belt trained on the driveshaft wheel. Thevortex transmission comprises a vortex drive pulley on which the vortexdrive belt is trained to transfer rotation of the vortex drive motor tothe vortex drive pulley, a vortexing wheel, a shaft rotatably couplingthe vortex drive pulley and the vortexing wheel, at least two rotatingvortexing elements coupled to the vortexing wheel such that rotation ofthe vortexing wheel causes a corresponding rotation of the rotatingvortexing elements, and an eccentric coupling extending from each of therotating vortexing elements at a position that is offset with respect toan axis of rotation of the corresponding rotating vortexing element. Thecontainer support platform is coupled to the eccentric couplings suchthat rotation of the vortexing elements imparts powered movement of thecontainer support platform in the orbital path via the eccentriccouplings.

According to other aspects of the disclosure, the fluid container mixingapparatus further comprises a counterweight attached to and rotatablewith the shaft rotatably coupling the vortex drive pulley and thevortexing wheel.

According to other aspects of the disclosure, each eccentric couplinghas the same offset with respect to the axis of rotation of itscorresponding rotating vortexing element.

According to other aspects of the disclosure, the vortexing wheelcomprises a vortexing pulley, each rotating vortexing element comprisesa vortexing idler pulley, and the vortex transmission further comprisesa belt coupling the vortexing pulley to the vortexing idler pulleys.

According to other aspects of the disclosure, the fluid container mixingapparatus further comprises one or more belt tensioners configured foradjusting the tension of the belt coupling the vortexing pulley to thevortexing idler pulleys.

According to other aspects of the disclosure, each belt tensionercomprises a slide, a tension wheel rotatably mounted to the slide andbearing against the belt coupling the vortexing pulley to the vortexingidler pulleys, and a tension adjuster screw configured to fix the slideand the tension wheel at a position that provides the desired tension inthe belt.

According to other aspects of the disclosure, the vortexing idlerpulleys are disposed at a common radial distance from an axis ofrotation of the vortexing pulley.

According to other aspects of the disclosure, the vortexing idlerpulleys are disposed at equal angular intervals with respect to thevortexing pulley.

According to other aspects of the disclosure, the vortexing wheelcomprises a vortexing gear, and the vortex transmission furthercomprises a gear train associated with each eccentric coupling wherebyeach rotating vortexing element comprises a gear of the associated geartrain. Each gear train is constructed and arranged to rotationallycouple each eccentric coupling with the vortexing gear.

According to other aspects of the disclosure, each gear train comprisesa transfer gear engaged with the vortexing gear and with the rotatingvortexing element.

According to other aspects of the disclosure, the container supportplatform comprises a turntable and a fluid container tray attached tothe turntable.

According to other aspects of the disclosure, the container supportplatform comprises a plurality of container receptacles, each configuredto receive a fluid container.

According to other aspects of the disclosure, the plurality of thecontainer receptacles comprise at least two different sizes.

According to other aspects of the disclosure, each receptacle includesan opening through which a machine-readable code on the fluid containerheld in the receptacle can be read.

According to other aspects of the disclosure, each container receptacleincludes a fluid container retainer element configured to releasablyhold a container within the receptacle.

According to other aspects of the disclosure, the fluid containerretainer element comprises a resilient element configured to compresswhen a container is placed into the container receptacle and toresiliently expand to press the container against a wall of thecontainer receptacle.

According to other aspects of the disclosure, the fluid container mixingapparatus further comprises feedback sensors configured to indicate aposition or status of at least one of the indexing drive system and thevortex drive system.

According to other aspects of the disclosure, the fluid container mixingapparatus further comprises a machine code reader constructed andarranged to read a machine-readable code on a fluid container carried onthe container support platform.

According to other aspects of the disclosure, the machine code readercomprises a bar code reader.

According to other aspects of the disclosure, the machine code readercomprises a radio frequency reader.

According to other aspects of the disclosure, the fluid container mixingapparatus comprises three vortexing elements, each of the rotatingvortexing element comprising a vortexing idler pulley. The vortextransmission further comprises a belt coupling the vortexing pulley totwo of the vortexing idler pulleys; the apparatus further. The apparatusfurther includes a first belt tensioner configured to adjust the tensionof the belt and located between the vortexing pulley and one of the twovortexing idler pulleys, a second belt tensioner configured to adjustthe tension of the belt and located between the vortexing pulley and theother of the two vortexing idler pulleys, and a third belt tensionerconfigured to adjust the tension of the belt and located between the twovortexing idler pulleys. The first, second, and third belt tensionersare configured to adjust the length of belt between the vortexing pulleyand either of the two vortexing idler pulleys and between the twovortexing idler pulleys, to adjust the relative phase of the eccentriccouplings associated with the two vortexing idler pulleys.

According to other aspects of the disclosure, the fluid container mixingapparatus further comprises one or more containers supported on thecontainer support platform and including an evaporation-limiting insertcomprising a tubular body extending into the container from an openingof the container and having one or more holes formed therein to permitfluid to flow into or out of a space inside the tubular body.

According to other aspects of the disclosure, the evaporation-limitinginsert has an irregular bottom edge such that at least a portion of thebottom edge is not perpendicular to a longitudinal axis of the tubularbody and whereby a gap is formed between the bottom edge and a bottomsurface of the container when the evaporation-limiting insert is fullyinserted into the container.

According to other aspects of the disclosure, the evaporation-limitinginsert further includes a retainer feature configured to engage aportion of the container to secure the insert within the container.

According to other aspects of the disclosure, the retainer featurecomprises a detent configured to engage an inside surface of thecontainer.

According to other aspects of the disclosure, the retainer featurecomprises two or more outwardly splayed tabs formed at a top portion ofthe tubular body and configured to deflect inwardly when the insert isinserted into a container and to press resiliently against an insidesurface of the container.

Other aspects of the disclosure are embodied in a method of selectivelytransporting a plurality of fluid containers or agitating the fluidcontainer to mix the contents of the fluid containers. The methodcomprises supporting the plurality of fluid containers on a containersupport platform, moving the container support platform to index thefluid containers by sequentially placing each of the containers in oneor more predetermined positions, and agitating the fluid containers tomix the contents of the fluid containers by moving the container supportplatform in a vortexing motion comprising moving the container supportplatform in an orbital path about an orbital center, wherein the movingstep and the agitating step are performed independently.

According to other aspects of the disclosure, moving the containersupport platform to index the fluid containers comprises rotating thefluid support about an axis of rotation.

According to other aspects of the disclosure, the method furthercomprises monitoring a position or status of container support platformduring at least one of the moving step and the agitating step.

According to other aspects of the disclosure, each of the plurality offluid containers contains machine readable identification indicia thatis read by a machine code reader during the moving step or while pausingthe moving step.

According to other aspects of the disclosure, the method furthercomprises supporting one or more containers on the container supportplatform and providing at least one of the containers with anevaporation-limiting insert comprising a tubular body extending into thecontainer from an opening of the container and providing one or moreholes in the tubular body to permit fluid to flow into or out of a spaceinside the tubular body.

According to other aspects of the disclosure, the method furthercomprises providing the evaporation-limiting insert with an irregularbottom edge such that at least a portion of the bottom edge is notperpendicular to a longitudinal axis of the tubular body and whereby agap is formed between the bottom edge and a bottom surface of thecontainer when the evaporation-limiting insert is fully inserted intothe container.

According to other aspects of the disclosure, the method furthercomprises providing the evaporation-limiting insert with a retainerfeature configured to engage a portion of the container to secure theinsert within the container.

Other aspects of the disclosure are embodied in an evaporation-limitinginsert for a container comprising a tubular body and an irregular edgeat one end of the tubular body. The tubular body extends into thecontainer from an opening of the container and has one or more holesformed therein to permit fluid to flow into or out of a space inside thetubular body. At least a portion of the irregular edge is notperpendicular to a longitudinal axis of the tubular body so that a gapis formed between the irregular edge and a bottom surface of thecontainer when the evaporation-limiting insert is fully inserted intothe container.

According to other aspects of the disclosure, the evaporation-limitinginsert includes a retainer feature configured to engage a portion of thecontainer to secure the insert within the container.

According to other aspects of the disclosure, the retainer featurecomprises a detent configured to engage an inside surface of thecontainer.

According to other aspects of the disclosure, the retainer featurecomprises two or more outwardly splayed tabs formed at a top portion ofthe tubular body and configured to deflect inwardly when the insert isinserted into a container and to press resiliently against an insidesurface of the container.

Other features and characteristics of the present disclosure, as well asthe methods of operation, functions of related elements of structure andthe combination of parts, and economies of manufacture, will become moreapparent upon consideration of the following description and theappended claims with reference to the accompanying drawings, all ofwhich form a part of this specification, wherein like reference numeralsdesignate corresponding parts in the various figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form partof the specification, illustrate various, non-limiting embodiments ofthe present disclosure. In the drawings, common reference numbersindicate identical or functionally similar elements.

FIG. 1 is a top perspective view of a fluid container mixing apparatusembodying aspects of the present disclosure.

FIG. 2 is a partial enlarged top perspective view of the apparatus.

FIG. 3 is a bottom perspective view of the apparatus.

FIG. 4 is a top perspective view of the apparatus with a container trayand turntable of the apparatus removed.

FIG. 5 is a top plan view of the apparatus with the container tray andturntable removed.

FIG. 6 is a top perspective view of the apparatus with the containertray removed and showing the turntable of the apparatus.

FIG. 7 is a partial cross-sectional view of the apparatus along the lineVII-VII in FIG. 5.

FIG. 8 is a partial cross-sectional view of the apparatus along the lineVIII-VIII in FIG. 5.

FIG. 9 is a top perspective view of an alternate embodiment of a fluidcontainer mixing apparatus embodying aspects of the disclosure shownwithout a container tray or a turntable.

FIG. 10 is a top perspective view of the apparatus shown in FIG. 9.

FIG. 11 is a cross sectional view of the apparatus along the line XI-XIin FIG. 9 and showing a turntable and container tray.

FIG. 12 is a schematic view of a power and control system of the fluidcontainer mixing apparatus.

FIG. 13 illustrates the vortex motion of the apparatus.

FIG. 14 is a perspective view of an evaporation-limiting containerinsert.

FIG. 15 is a cross-sectional, perspective view of the container insertinserted into a container.

FIG. 16 is a perspective view of an evaporation-limiting containerinsert according to an alternate embodiment.

FIG. 17 is a cross-sectional, perspective view of an alternateembodiment the container insert inserted into a container.

DETAILED DESCRIPTION

Unless defined otherwise, all terms of art, notations and otherscientific terms or terminology used herein have the same meaning as iscommonly understood by one of ordinary skill in the art to which thisdisclosure belongs. Many of the techniques and procedures described orreferenced herein are well understood and commonly employed usingconventional methodology by those skilled in the art. As appropriate,procedures involving the use of commercially available kits and reagentsare generally carried out in accordance with manufacturer definedprotocols and/or parameters unless otherwise noted. All patents,applications, published applications and other publications referred toherein are incorporated by reference in their entirety. If a definitionset forth in this section is contrary to or otherwise inconsistent witha definition set forth in the patents, applications, publishedapplications, and other publications that are herein incorporated byreference, the definition set forth in this section prevails over thedefinition that is incorporated herein by reference.

As used herein, “a” or “an” means “at least one” or “one or more.”

This description may use relative spatial and/or orientation terms indescribing the position and/or orientation of one component, apparatus,location, feature, or a portion thereof. Unless specifically stated, orotherwise dictated by the context of the description, such terms,including, without limitation, top, bottom, above, below, under, on topof, upper, lower, left of, right of, in front of, behind, next to,adjacent, between, horizontal, vertical, diagonal, longitudinal,transverse, etc., are used for convenience in referring to suchcomponent, apparatus, location, feature, or a portion thereof in thedrawings and are not intended to be limiting.

A fluid container mixing apparatus embodying aspects of the presentdisclosure is indicated by reference number 100 in FIGS. 1, 2, and 3.The apparatus 100 includes a container support platform configured tohold one or more fluid container and to be selectively indexed topresent each container to a predetermined position. In the presentdisclosure “index” or “indexing” the containers refers to moving thecontainers carried on the fluid container support platform toselectively and sequentially place each of the containers in one or morepredetermined positions. In the illustrated embodiment, the containersupport platform is rotatable about an axis of rotation. In otherembodiments, indexing of the containers may comprise moving thecontainers on one or more carriers moving in a predefined path having acircular, oval or other continuous shape. In the illustrated embodiment,the container support platform comprises a container tray 110,configured to hold a plurality of fluid containers, and a turntable 150to which the container tray 110 is attached.

The container support platform is also configured to be movable in avortexing, or orbital path about an orbital center.

In the context of the present description, the terms vortex, vortexing,orbit, orbital, or similar terms when used to describe the motion of thefluid container support platform (fluid container tray 110 and turntable150) refers to a path of motion whereby the entire fluid containersupport platform moves about an orbital, or vortex, center independentlyof the indexing of the container support platform (e.g., an rotation orspinning of the fluid container support platform about an axis ofrotation of the platform). This is shown in FIG. 13, which illustratesthe vortex motion of the turntable 150. During the vortex motion, theturntable 150 is moved such that the center “C” of the turntable 150orbits about a vortex circle C_(V) centered at an orbital center C_(O)through positions C₁, C₂, C₃, C₄ as the turntable moves throughpositions 150 ₁, 150 ₂, 150 ₃, 150 ₄.

Apparatus 100 further includes a turntable drive system 200 coupled tothe fluid container support platform and constructed and arranged toeffect powered indexing of the fluid container support platform. In theillustrated embodiment, the turntable drive system 200 effects poweredrotation of the fluid container support platform about its axis ofrotation. Apparatus 100 further includes a vortex drive system 300coupled to the fluid container support platform and configured to effectvortexing, orbital movement of the fluid container support platform boutits orbital center.

The turntable drive system 200 and the vortex drive system 300, in oneembodiment, are independent of each other such that the container trayand turntable can be independently indexed (e.g., rotated about acentral rotational axis) or vortexed about a plurality of vortex axes.The turntable drive system 200 and the vortex drive system 300 may alsooperate simultaneously to simultaneously rotate and vortex the containertray, which may facilitate improved mixing of the contents of thecontainers.

As shown in FIGS. 1 and 2 the container tray 110 includes a plurality ofcup-like, generally cylindrical container receptacles and may includecontainer receptacles of varying sizes, such as larger containerreceptacles 112 and smaller container receptacles 116, configured toreceive and hold fluid containers (e.g., bottles) 126, 128, 130 ofvarying sizes. In addition, to accommodate different container sizes,separate drop-in adapters may be provided for the receptacles 112, 116.The adaptor will permit the introduction and fixed placement of fluidcontainers in receptacles 112, 116 that have diameters that are smallerthan the diameter of receptacles 112, 116. The container tray 110 ispreferably circular in shape, and the container receptacles 112, 116,are preferably symmetrically disposed about a central axis of thecontainer tray 110. In the illustrated embodiment, container receptacles112 include outwardly facing openings 114, and container receptacles 116include outwardly facing openings 118. The openings 114, 118 areconfigured to enable a machine code reader 124 mounted on a machine codereader bracket 122 to read a machine code disposed on a container andaligned with the opening 114 or 118. Machine code reader 124 may be abarcode reader configured to read one-dimensional and/or two-dimensionalbarcodes formed on labels placed on the containers 126, 128, 130 placedin the container receptacles 112, 116. Other machine code reader devicesare contemplated, such as radio frequency identification. Each containerreceptacle 112, 116 may include a receptacle-empty label that is read bythe reader 124 when no container is held in the associated receptacle.

Container tray 110 may be formed of any suitable material, and, in oneexample, it is formed of molded plastic.

The container tray 110 further includes a container retainer element 120disposed in each container receptacle 112, 116. The retainer element 120may be a resilient element configured to compress when a container isplaced into the container receptacle and to resiliently expand to pressthe container against a wall of the container receptacle. In theillustrated embodiment, the container retainer element 120 comprises aspring clip 120 formed by a bowed strip of spring steel and attached tothe container tray 110 at a radially inward portion of each containerreceptacle 112, 116. Alternatively, the spring clip may be fabricatedfrom injection molded plastic, rather than bent metal. As will beappreciated by persons of ordinary skill in the art, the containerretainer element 120 is configured to flex inwardly when anappropriately-sized container is placed in the container receptacle 112or 116, and the resilience of the retainer element 120 will urge thecontainer radially outwardly toward the opening 114 or 118 of therespective container receptacle 112 or 116. One purpose of the retainerelement 120 is to prevent the containers from rotating within theirrespective container receptacle 112 or 116 (which would misalign thebarcode label and prevent reading) and to prevent containers fromrattling loosely in their respective container receptacle 112 or 116.The retainer element 120 may be configured to accommodate containers ofdifferent sizes. As shown in FIG. 1, containers 128 and 130 are ofdifferent sizes and are both held in a “large” receptacle 112. Thespring clip 120 shown in FIG. 1 can compress to a large extent toaccommodate the larger container 128 and can compresses to a lesserextent and can expand to securely hold the smaller container 130 withinthe relatively over-sized receptacle 112.

As shown in FIGS. 3 and 6, the turntable 150 comprises a disk may becircular in shape and is configured to be rotatable about a central axisthereof. In other embodiments, the turntable has other shape and each isconfigured to be rotatable about an axis that is generally perpendicularto the plane of the turntable. Turntable 150 may be formed from anysuitable material having sufficient strength, rigidity, andmachinability that is preferably, in certain embodiments, lightweight.Suitable exemplary materials include aluminum, stainless steel, or avariety of known engineering plastics.

Three slots 152 are formed through the turntable 150. The turntable 150is further engaged by three eccentric couplings 342, 352, 362 extendingthrough corresponding openings formed in the turntable 150. Awedge-shaped counterweight 180 is disposed on a shaft 316 extendingaxially through the turntable 150. Further details regarding theconstruction and functionality of the slots 152, eccentric couplings342, 352, 362, counterweight 180, and shaft 316 will be described below.

As shown in FIGS. 2 and 6, the container tray 110 may be secured to theturntable 150 by any suitable means, including mechanical fasteners,such as screws 156, extending through the container tray 110 and intoscrew-receiving openings formed about the perimeter of the turntable150.

Details of an exemplary turntable drive system 200 are shown in FIGS. 3,4 and 5. The turntable drive system 200 includes a turntable drive motor202 coupled to the container support platform. In the illustratedembodiment, the turntable drive motor 202 has a driveshaft wheel 204attached to an output shaft of the motor 202. A rotatable turntabledrive pulley 208 is coupled to the turntable 150. A turntable drive belt206 extends over the drive shaft wheel 204 of the turntable drive motor202 and the turntable drive pulley 208 such that rotation of thedriveshaft wheel 204 by the turntable drive motor 202 effects poweredrotation, via the turntable drive belt 206, of the turntable drivepulley 208 and the turntable 150.

Turntable drive motor 202 is preferably a stepper motor and may includea rotary encoder for controlling and monitoring the rotational positionof the motor 202 and the turntable drive pulley 208 and turntable 150rotated thereby. Turntable pulley 208 may include a rotational feedbacksensor, such as a home flag. In the illustrated embodiment, a coupling209 projects down from the turntable pulley 208 (see FIG. 3), andcoupling 209 may be detected by a home flag sensor (e.g., a slottedoptical sensor) (not shown) mounted beneath pulley 208. Other types ofsensors may be used for indicating a home position. Such sensors maycomprise proximity sensors, magnetic sensors, capacitive sensors, etc.

Details of a vortex drive system 300 are shown in FIGS. 3, 4, 5, 7 and8. As shown in FIGS. 3 and 4, the vortex drive system 300 includes avortex drive motor 302 coupled to the container support platform. In theillustrated embodiment, the vortex drive motor 302 has a driveshaftwheel 304. A vortex drive belt 306 couples the driveshaft wheel 304 ofthe vortex drive motor 302 to a vortex transmission 308. Alternatively,the vortex drive motor 302 may be coupled to the vortex transmission byone or more gears or other means known to those of ordinary skill forcoupling motor power. The vortex transmission is coupled to the vortexdrive motor 302 and to the fluid container support platform (fluidcontainer tray 110 and turntable 150 in the illustrated embodiment) andis constructed and arranged to convert powered rotation of the outputshaft of the vortex drive motor 302 into orbital movement of the fluidcontainer support platform.

In the illustrated embodiment, the vortex transmission 308 includes avortex drive pulley 310 around which the vortex drive belt 306 istrained. The vortex drive pulley 310 is attached to a shaft 316 that isrotatably mounted within shaft bearing 318. Shaft bearing 318 includes acylindrical housing 320 and a bearing mounting flange 324 extendingradially from the cylindrical housing 320. Shaft 316 extends thought thecylindrical housing 320 and it rotatably supported therein by twolongitudinally-spaced needle bearing braces 322, 323. A vortexing wheel,which in the illustrated embodiment comprises a vortexing pulley 326, isattached to the shaft 316 at an intermediate portion thereof, and thecounterweight 180 is attached to the shaft 316 at its upper end.

Vortex drive motor 302 is preferably a stepper motor and may include arotary encoder. The vortex transmission may include feedback sensors. Inthe illustrated embodiment, an index wheel 312 is attached to the vortexdrive pulley 310, and a rotational position of the index wheel 312,e.g., a “home” position, may be detected by a sensor 314, which maycomprise a slotted optical sensor. Other types of sensors may be usedfor indicating a home position. Such sensors may comprise proximitysensors, magnetic sensors, capacitive sensors, etc.

In the illustrated embodiment, as shown in FIGS. 4 and 5, each of theeccentric couplings 332, 342, 352 extends above a correspondingvortexing rotating element which, in the illustrated embodiment,comprises a respective idler pulley 330, 340, 350. The vortexing idlerpulleys 330, 340, 350 are mounted on and rotate with the turntable drivepulley 208 about the rotational center of the drive pulley 208. Theeccentric couplings 342, 352, 362, or portions thereof, extend throughthe turntable 150 as shown in FIG. 6, so as to rotationally couple theturntable 150 to the turntable drive pulley 208 such that rotation ofthe turntable drive pulley causes a corresponding rotation of theturntable 150.

The eccentric couplings 332, 342, 352 also comprise a portion of thevortex transmission 308. Some or all of the eccentric couplings 332,342, 352 are coupled to the vortexing wheel to impart eccentric rotationto the coupled eccentric couplings. In the embodiment shown in FIGS. 4and 5, the vortexing idler pulleys 330, 340, 350 are each rotatablymounted to the turntable drive pulley 208 and are coupled to thevortexing pulley 326. The axes of rotation of the idler pulleys 330,340, 350 are each located at the same radial distance from the center ofthe vortexing pulley 326, which corresponds to the center of shaft 316,although is it not required that the axes be located at the same radialdistance. Also, the vortexing idler pulleys 330, 340, 350 are positionedin an equiangular arrangement about the vortexing pulley 326 at 120°intervals, although it is not required that the vortexing pulleys bespaced at equal angular intervals.

Referring now to FIGS. 4 and 5, above the turntable drive pulley 208, aserpentine belt 328 extends around the vortexing pulley 326, thevortexing idler pulley 330, and the vortexing idler pulley 340. Rotationof the vortex drive pulley 310 by the vortex drive belt 306 and thevortex motor 302 causes rotation of the shaft 316 and thereby rotatesthe vortexing pulley 326. As can be appreciated from FIGS. 4 and 5,rotation of the vortexing pulley 326 causes corresponding rotation ofthe vortexing idler pulleys 330 and 340, via the serpentine belt 328.

Appropriate tension in the serpentine belt 328 is maintained by tensionadjusters 380, 390 and 400. Tension adjuster 380 is located between thevortexing pulley 326 and vortexing idler pulley 330 and comprises aslide 382 disposed within a surface slot 220 formed in the turntabledrive pulley 208, a tension wheel 386 rotatably mounted to the slide382, and a tension adjuster screw 384 extending through the slide 382and through a through slot 210 formed in the turntable drive pulley 208.The tension wheel 386 bears against the serpentine belt 328, and tensionin the belt 328 is adjusted by loosening the tension adjuster screw 384so as to permit the slide 382 to move within surface slot 220 relativeto the serpentine belt 328. The tension adjuster screw 384 is thenretightened to fix the slide 382 and the tension wheel 386 at a positionthat provides the desired tension in the serpentine belt 328.

Tension adjuster 390 is located between vortexing idler pulley 330 andvortexing idler pulley 340 and comprises a slide 392 disposed within asurface slot 220 formed in the turntable drive pulley 208, a tensionwheel 396 rotatably mounted to the slide 392, and a tension adjusterscrew 394 extending through the slide 392 and through a through slot 210formed in the turntable drive pulley 208. The tension wheel 396 bearsagainst the serpentine belt 328, and tension in the belt 328 is adjustedby loosening the tension adjuster screw 394 so as to permit the slide392 to move within the surface slot 220 relative to the serpentine belt328. The tension adjuster screw 394 is then retightened to fix the slide392 and the tension wheel 396 at a position that provides the desiredtension in the serpentine belt 328.

Similarly, tension adjuster 400 is located between the vortexing pulley326 and the vortexing idler pulley 340 and comprises a slide 402disposed within a surface slot 220 formed in the turntable drive pulley208, a tension wheel 406 rotatably mounted to the slide 402, and atension adjuster screw 404 extending through the slide 402 and through athrough slot 210 formed in the turntable drive pulley 208. The tensionwheel 406 bears against the serpentine belt 328, and tension in the belt328 is adjusted by loosening the tension adjuster screw 404 so as topermit the slide 402 to move within the surface slot 220 relative to theserpentine belt 328. The tension adjuster screw 404 is then retightenedto fix the slide 402 and tension wheel 406 at a position that providesthe desired tension in the serpentine belt 328.

There are three tension adjusters 380, 390, 400—one for each span of theserpentine belt 328 between vortexing idler pulley 330 and vortexingidler pulley 340, between vortexing idler pulley 340 and vortexingpulley 326, and between vortexing pulley 326 and vortexing idler pulley330—in order to adjust the phase of the eccentric couplings 332, 342,352 relative to each other. The tension adjusters 380, 390, 400 on theserpentine belt 328 serve at least a couple purposes. First, the tensionadjusters tension the belt 228. In addition, the tension adjusters 380,390, 400 clock the eccentric couplings 332, 342, 352 in phase. Thetension adjusters 380, 390, 400 also clock the counter weight 180 180degrees out-of-phase with the eccentric couplings 332, 342, 352. In oneembodiment, there are no adjustments of the eccentric couplings 332,342, 352 relative to the pulley teeth on the vortexing idler pulleys330, 340 and the vortexing pulley 326. Accordingly, the eccentriccouplings 332, 342, 352 and the counterweight 180 can be clockedin-phase by adjusting the belt length between each of the three pulleysidler pulleys 330, 340, 350.

It is important that each of the eccentric couplings 332, 342, and 352have the same amount of offset (i.e., eccentricity) with respect to therespective vortexing idler pulleys 330, 340, 350. Also, the rotationalpositions of the vortexing idler pulleys 330, 340, 350 must becoordinated so that each eccentric coupling 332, 342, 352 is at the samerotational position with respect to the axis of rotation of thecorresponding vortexing idler pulley 330, 340, 350, or the vortex drivesystem 700 may bind. This can be accomplished by adjusting the beltlength between the vortexing idler pulleys 330, 340, 350 using thetension adjusters 380, 390, 400 as described above.

As explained above, the eccentric couplings 332, 342, and 352 arecoupled to the turntable 150. Each of the eccentric couplings 332, 342,and 352 is positioned at an eccentric, or offset, location with respectto the rotational center of the corresponding vortexing idler pulley330, 340 and 350. Thus, rotation of the vortexing idler pulleys 330 and340, via the serpentine belt 328 and the vortexing pulley 326, causes anoscillating, vortexing motion of each of the eccentric couplings 332 and342 that is imparted to the turntable 150 coupled thereto. The vortexingidler pulley 350 in the illustrated embodiment is not coupled to thevortexing pulley 326 via the serpentine belt 328. The vortexing pulley350, with eccentric coupling 352 extending therefrom, is a follower thatprovides a third point of support for the turntable 150 and moves in thesame vortexing path with the turntable 150.

The vortex motion of the turntable 150, as caused by the vortex drivesystem 300, is illustrated in FIG. 13. As explained above, during thevortex motion, the turntable 150 is moved by the eccentric rotation ofthe eccentric couplings 332, 342, such that the center “C” of theturntable 150 orbits about a vortex circle C_(V) centered at an orbitalcenter C_(O) through positions C₁, C₂, C₃, C₄ as the turntable movesthrough positions 150 ₁, 150 ₂, 150 ₃, 150 ₄. During the vortex motion,every point of the turntable 150 orbits around a circle having the sameradius as C_(V). The radius of Cv corresponds to the amount of eccentricoffset of the eccentric couplings 332, 342, 352 with respect to the axesof rotation of the vortexing idler pulleys 330, 340, 350.

The purpose of the counterweight 180 is to minimize the vibrationgenerated by the apparatus so as to limit the vibration that will beimparted by the apparatus to an instrument or laboratory in which theapparatus is employed. The counterweight 180 is attached to shaft 316and is located beneath the container tray 110. The rotation pattern ofthe turntable 150 and container tray 110 relative to the motion of thecounterweight 180 is similar to that of a camshaft. In one embodiment,the mass×radius product of the counterweight 180 is equal to: (the massof the container support platform, i.e., the mass of the turntable 150and the container tray 110)×(its effective radius)+(½ the mass of a fullset of bottles occupying each container receptacle 112, 116 in thecontainer tray 110, e.g., fourteen bottles in container tray 110 shownin FIG. 1)×(the effective radius of the bottles).

Of course the mass of the counterweight 180 can vary, which will have aneffect on the resulting vibration of the apparatus depending on theliquid level of the bottles on the container tray 110. Selecting acounterweight mass equal to half the expected mass of a completecollection of full bottles provides a reasonable middle ground. Anyvibration in the apparatus is due to the varying fluid levels in thebottles to the extent the levels are above or below the ideal/calibratedmass of the counterweight. So, as a percentage of the overall mass ofthe apparatus, the potential variability of the mass of the fluid in thebottles is low, which provides for minimal vibrations.

Also, one could increase the mass of the turntable and container tray(and the counterweight) to reduce the overall effect of the massvariability caused by the changing liquid levels in the bottles, butthat would require larger turntable drive and vortex drive motors.

There are a number of benefits to providing the counterweight 180.First, the reduced vibrations achieved with the use of a counterweightimproves operational lifetime of the apparatus, and particularly thedrive motors, since the drive systems will be subject to decreasedvibration levels. Furthermore, the apparatus may be employed in adiagnostic instrument that requires very precise movements and fluiddispensing with very small spatial tolerances for accurate operation ofits many moving parts, such as a fluid dispensing pipettor. Theintroduction of excessive vibrations into such a calibrated environmentcould negatively impact the accurate positioning of the pipettor and/orother modules. Such inaccuracies could result in, for example, systemfailures, contamination, sample processing failures, and related issues.

Details of the rotational mounting of the turntable drive pulley 208 andthe vortexing pulley 326 are shown in FIG. 7, which is a partialtransverse cross-section of the apparatus along the line VII-VII in FIG.5. As shown in FIG. 7, the turntable drive pulley 208 is rotationallysupported with respect to the non-rotating cylindrical housing 320 ofthe shaft bearing 318 by means of upper and lower bearing races 216,218. The shaft 316 is rotationally supported within the shaft bearing318 by the spaced-apart needle bearing races 322, 323 located within thefixed, non-rotating cylindrical housing 320 of the shaft bearing 318.Bearing races 216, 218 rotationally isolate the turntable drive pulley208 from the vortex transmission 308. Accordingly, the turntable drivepulley 208 is able to rotate independently of the shaft 316 and thevortex drive pulley 310 and vortexing pulley 326 connected thereto.Moreover, the vortex transmission 308, comprising the shaft 316, thevortex drive pulley 310 and the vortexing pulley 326, can rotateindependently of the turntable drive system 200, comprising theturntable drive motor 202, the turntable drive belt 206, and theturntable drive pulley 208. Thus, the container tray 110 can beselectively rotated by the turntable drive system 200 to place any ofthe containers carried thereon into a desired rotational position, orthe entire container tray 110 can be moved in a vortexing motion by thevortex drive system 300 to agitate the contents of the containerscarried thereon. The rotating motion and the vortexing motion can beperformed independently. In certain particularly preferred embodiments,the rotating motion and vortexing motion are performed independently.

Details of the vortexing idler pulley 340 and details of the tensionadjuster 400 are shown in FIG. 8, which is a partial cross-section ofthe apparatus 100 along the line VIII-VIII in FIG. 5. The vortexingidler pulley 340 comprises a pulley wheel 348 and a central idler pulleyshaft 346 extending downwardly from the pulley wheel 348. The pulleywheel 348 is hollowed out on its underside and nests upon a raisedcylindrical boss 212 of the turntable drive pulley 208. The idler pulleyshaft 346 extends through a central axial opening formed through theraised boss 212 and is rotationally supported at spaced apart bearingraces 354 and 356. The end of the idler pulley shaft 346 terminateswithin a cylindrical recess 214 formed in the underside of the turntabledrive pulley 208. A frustoconical shim washer 358 disposed on a lowerend of the idler pulley shaft 346 bears against the inner race of thelower race bearing 356, and a snap retainer clip 360 on the end of theshaft 346 secures the idler pulley 340 in place. The end of the idlershaft pulley 346, the shim washer 358, and the snap retainer clip 360are all disposed within the recess 214 so that no portions of thevortexing idler pulley 340 extends below the bottom of the turntabledrive pulley 208.

The eccentric coupling 342 comprises an eccentric shaft 364 extendingupwardly from the pulley wheel 348 at an offset position with respect tothe idler pulley shaft 346. The eccentric shaft 364 extends through anopening in the turntable 150 and is rotationally supported by a bearingrace 368 disposed within a recess 154 formed in the underside of theturntable 150 with a frustoconical shim washer 370 disposed between thetop of the pulley wheel 348 and the bottom of the bearing race 368. Acap 366 is rotatably mounted on an upper end of the eccentric shaft 364extending above the turntable 150 so as to be rotatable with respect tothe shaft 364.

The vortexing idler pulleys 330 and 350 each comprise an assembly thatis substantially identical to that of vortexing idler pulley 340 shownin FIG. 8.

The tension adjuster 400 includes a wheel shaft 410 extending upwardlyfrom the slide 402. The tension wheel 406 is coaxially mounted on thewheel shaft 410 and is rotatably supported with respect to the wheelshaft 410 by upper and lower bearing races 412, 414 secured in place bya frustoconical shim washer 416 and a snap retainer clip 418 that aredisposed within an upper recess of the tension wheel 406. The tensionadjusting screw 404 extends through the slot 210 formed through theturntable drive pulley 208. The slide 402 is disposed within the surfaceslot 220 formed in the upper surface of the turntable drive pulley 208.Slot 152 formed in the turntable 150 provides access to the tensionadjuster 400. The orbital path of the turntable 150 with respect to theturntable drive pulley 208 due to the eccentric rotation of theeccentric couplings 332, 342, 352 causes the positions of the slots 152to move with respect to the tension adjusters 380, 390, 400. Thus, theturntable 150 can be moved with respect to the turntable drive pulley208 to align the slots with the eccentric couplings 332, 342, 352.

Tension adjusters 380 and 390 comprise an assembly that is substantiallyidentical to that of tension adjuster 400 shown in FIG. 8.

An alternate embodiment of a fluid mixing apparatus embodying aspects ofthe present disclosure is indicated by reference number 500 in FIGS. 9,10 and 11. The apparatus 500 includes a container support platformconfigured to hold one or more fluid container and to be indexed toselectively present fluid containers to a defined position. In theillustrated embodiment, the container support platform is configured tobe rotatable about an axis of rotation. The container support platformis also configured to be movable in a vortexing, or orbital path aboutan orbital center.

In the illustrated embodiment, the container support platform comprisesa fluid container tray 510 and a turntable 550 (FIG. 11).

Apparatus 500 includes a turntable drive system 600 coupled to thecontainer support platform and constructed and arranged to effectpowered rotation of the fluid container support platform about its axisof rotation. Apparatus 500 further includes a vortex drive system 700coupled to the fluid container support platform and configured to effectvortexing, orbital movement of the fluid container support platformabout an orbital center. FIGS. 9 and 10 are top perspective views of theturntable drive system 600 and the vortex drive system 700 of theapparatus shown without the turntable or fluid container tray. FIG. 11is a cross section along the line XI-XI of FIG. 9 and shows the vortexdrive system 700, the turntable 550, and the container tray 510.

Referring to FIGS. 9 and 10, the turntable drive system 600 includes aturntable drive motor 602, preferably a stepper motor, having adriveshaft gear 604 attached to an output shaft of the motor. Theturntable drive motor 602 is coupled to the fluid container supportplatform by the engagement of the driveshaft gear 604 with theperipheral gear teeth of a turntable drive gear 608. Rotation of thedriveshaft gear 604 by the turntable drive motor 602 causes acorresponding rotation of the turntable drive gear 608 about its axis ofrotation.

Referring to FIG. 10, the vortex drive system 700 includes a vortexdrive motor 702 having a driveshaft wheel 704 coupled to a vortex drivepulley 710 of a vortex transmission 708 by means of a vortex drive belt706 (or gears or other known means for coupling the vortex drive motor702). Referring to FIG. 11, the vortex transmission 708 of apparatus 500further includes a vortexing wheel, which, in the illustratedembodiment, comprise vortexing gear 726 disposed above the turntabledrive gear 608 and connected by a shaft 716 to the vortex drive pulley710. A counterweight 180 is attached to an upper, free end of the shaft716. The shaft 716 is rotationally supported within a fixed bearinghousing 720, for example, using one or more bearing races or other formsof bearings (not shown). The turntable drive gear 608 is rotationallysupported on the outside of the bearing housing 720, also by suitablebearings, bearing races, or other suitable means (not shown), so thatthe turntable drive gear 608 and the vortex drive pulley 710 and shaft716 can rotate independently of each other.

The vortex transmission 708 further includes eccentric vortex couplings736, 746, 756. As shown in FIGS. 9 and 10, each of the eccentriccouplings 736, 746, 756 extends above a rotating vortexing elementwhich, in the illustrated embodiment, comprises a respective end gear734, 744, 754. Each eccentric vortex coupling 736, 746, 756 is coupledto the vortexing gear 726 by a gear train. Specifically, the eccentricvortex coupling 736 is rotated by a gear train 730 comprising a transfergear 732 directly engaged with the vortexing gear 726 and end gear 734that is directly engaged with the transfer gear 732. The eccentricvortexing coupling 736 extends axially from the end gear 734 and iseccentrically offset with respect to the axis of rotation of the endgear 734.

The eccentric vortex coupling 746 is rotated by a gear train 740comprising a transfer gear 742 directly engaged with the vortexing gear726 and end gear 744 that is directly engaged with the transfer gear742. The eccentric vortexing coupling 746 extends axially from the endgear 744 and is eccentrically offset with respect to the axis ofrotation of the end gear 744.

The eccentric vortex coupling 756 is rotated by a gear train 750comprising a transfer gear 752 directly engaged with the vortexing gear726 and end gear 754 that is directly engaged with the transfer gear752. The eccentric vortexing coupling 756 extends axially from the endgear 754 and is eccentrically offset with respect to the axis ofrotation of the end gear 754.

The end gears 734, 744, 754 are each rotatably mounted to the turntabledrive gear 608. The axes of rotation of the end gears 734, 744, 754 areeach located at the same radial distance from the center of thevortexing gear 726, which corresponds to the center of shaft 716,although it is not required that the gears be located at the same radialdistance. Also, the end gears 734, 744, 754 are positioned in anequiangular arrangement about the vortexing gear 726 at 120° intervals,although it is not required that he end gears be positioned at equalangular intervals.

In alternate embodiments, the gear trains may comprise more than twogears, so long as there is an even number of gears (e.g., 2, 4, 6,etc.), in the gear train so that the vortexing gear 726 rotates in thesame direction as the end gears 734, 744, 754 in order to properlycounterbalance the mechanism.

Rotation of each of the end gears 734, 744, 754 causes correspondingvortexing, orbital movement of the corresponding eccentric couplings736, 746, 756 that is imparted to the container tray 510. Thus, via thegear trains 730, 740, 750, rotation of the vortexing gear 726 causescorresponding rotations of the eccentric vortex couplings 736, 746 756that imparts the vortexing orbital movement to the container tray 510.

As shown in FIG. 11, eccentric vortex coupling 756 extends from shaft758 rotationally mounted within the turntable drive gear 608 and havinga central axis of rotation that defines the central axis of the end gear754. Shaft 758 may be supported with respect to a through hole formedthrough the turntable drive gear 608 by means of bearings (not shown).The coupling 756 is offset from the axis of rotation of the shaft 758.Each of the eccentric vortex couplings 736 and 746 has a constructionthat is similar to that of eccentric vortex coupling 756.

The eccentric vortex couplings 736, 746, 756 extend through theturntable 550 and thereby rotationally couple the turntable 550 with theturntable drive gear 608 so that rotation of the turntable drive gearabout its axis of rotation causes a corresponding rotation of theturntable 550 and the fluid container tray 510 attached thereto.

FIG. 12 is a schematic view of the control system for controllingoperation of the fluid container mixing apparatus embodying aspects ofthe present disclosure. A fluid container mixing apparatus configured toprovide independent positioning, e.g., by rotation of the apparatus, ofone or more containers carried on the apparatus and vortexing of thecontainers to agitate the contents of the containers is indicated byreference number 800 in FIG. 12. Apparatus 800 may correspond toapparatus 100 or apparatus 500 described above. The positioning motionof the apparatus is represented by the arrows “R”, which representsrotation of the apparatus about the center C. Vortexing of the apparatusis represented by the three arrows “V”. The rotation of the apparatus iseffected by an indexing drive system comprising an indexing motor 804that is coupled to the apparatus 800, as represented by double lines810, to effect powered rotation of the apparatus. Vortex motion V of theapparatus is effected by a vortex drive system comprising a vortex motor806 that is coupled to the apparatus 800, as represented by double lines812, to effect powered vortexing motion of the apparatus. The indexingmotor 804 and the vortex motor 806 are coupled to and controlled by acontroller 802 that is also connected to a controllable power supply814. Controller 802 provides power and operational control signals tothe indexing motor 804 and vortex motor 806. Controller 802 may alsoreceive data from the indexing motor 804 and the vortex motor 806 in theform of rotary encoder counts as well as other feedback sensor signals.Box 808 represents feedback sensors coupled to the mixing apparatus 800,such as a rotational home flag, a vortex position home flag, etc., andis connected to the controller 802 for providing positional, or otherstatus, feedback that is used in generating control signals foroperating the indexing motor 804 and the vortex motor 806.

Evaporation-Limiting Container Insert

The fluid contents of containers carried on the fluid container supportplatform of the mixing device 100 or 500 may comprise fluid solutions orsuspensions. Representative fluid contents may comprise reagentscontaining solid supports, such as silica or magnetically-responsiveparticles or beads. See, e.g., Boom et al., U.S. Pat. No. 5,234,809 andWeisburg et al., U.S. Pat. No. 6,534,273. Such solid supports can beuseful for immobilizing nucleic acids in a sample processing procedureto remove inhibitors of amplification and/or detection. Suitablereagents for this purpose include the target capture reagents describedabove. As discussed elsewhere in this disclosure, mixing of the fluidcontents, e.g., by agitating the container containing the fluidcontents, helps to maintain the suspended materials in suspension withinthe fluid.

Even in the absence of suspended particles or solid supports, it may bepossible for one or more components of a fluid solution to precipitateout of solution, potentially affecting the concentration of the solutionthat is drawn out of the container. Even small changes in concentrationscan have a deleterious impact on a test or assay performed with suchsolutions. Mixing the fluid contents, e.g., by agitating the containercontaining the fluid contents, may actually slow and/or reverse suchprecipitation.

The containers are typically carried in an open state to permit readyaccess to the fluid contents of each of the containers by a fluidtransfer apparatus, such as a robotic pipettor. The fluid transferapparatus may access the fluid contents of the container to withdrawfluid from the container and/or to dispense additional fluid into thecontainer. The fluid transfer apparatus may include a pipettorconfigured to detect a fluid surface within the container, e.g., for thepurpose of determining or verifying the height of the fluid within thecontainer, which can be used to calculate the volume of fluid remainingin the container. Suitable pipettors for this purpose are disclosed byLipscomb et al. in U.S. Pat. No. 6,914,555.

When the containers are in an open state, the fluid contents of thecontainers are exposed to the atmosphere and, therefore, are susceptibleto evaporation. Mixing only exacerbates this problem, as mixing resultsin increased exposure of a fluid surface to the atmosphere, therebypotentially accelerating the rate of evaporation.

An evaporation-limiting container insert for reducing the amount ofevaporation from a container is indicated by reference number 820 inFIGS. 14 and 15. The insert 820 includes an elongated tubular body 822with a plurality of holes 828 formed in a side wall of the tubular body822. In an exemplary embodiment, the tubular body 822 is cylindrical andhas a generally constant diameter from one end thereof to an oppositeend thereof. The holes 828 may be circular, as shown, or may haveanother shape. The shape of the holes 828 may be dictated bypracticalities of manufacturing. In one embodiment, the size of eachhole 828 is about 1/16 inch, but may be of any suitable size. When thefluid contents of the container include a suspension of solid orsemi-solid particles, the holes 828 should be sized to permit thepassage of the particles through the tubular body 822 of the containerinsert 820.

In an embodiment, the holes 828 may be longitudinally aligned along thetubular body 822 and may be provided on one or more sides of the tubularbody 822. There is no requirement that the holes 828 be aligned, asshown in the figures. The arrangement of the holes may be dictated byconsiderations, such as manufacturing practicalities. The holes 828 maybe provided in two or more groups—e.g., lines—of holes located atdiametrically opposed locations on the body 822 or otherwise spacedaround the body 822. In various embodiments, there are at least threeholes 828 on each of two opposed sides of the container insert 820, andthere may be 4, 5, 6 or more holes 828 on each of two opposed sides ofthe insert 820 in such embodiments.

In various embodiments, the insert 820 may include a beveled surface 826surrounding a top opening and an irregular or undulating bottom edge830.

FIG. 15 is a cross-sectional, perspective view of the container insert820 inserted into a representative container 840. In this embodiment,the insert 820 is inserted into the container 840 through an opening atthe top of a neck 842 of the container 840. In an exemplary embodiment,the outside dimension of the tubular body 822 (e.g., the outsidediameter) conforms to, i.e., is only slightly smaller than, the insidedimension (e.g., diameter) of the neck 842 so that the container insert820 snugly fits within the container 840. In various embodiments, aninsert retainer feature, such as a detent 824, resiliently engages theinside surface of the neck 842 to help retain the insert within thecontainer 840. The beveled surface 826 surrounding the top opening ofthe insert 820 will help to redirect a misaligned a fluid transferapparatus (e.g., pipettor tip component) toward the center of the insert820.

As shown in FIG. 15, the length of the container insert 820 may be suchthat a top end of the insert 820 is disposed at or just below the top ofthe container neck 842 and the lower end 830 of the insert 820 is incontact with the bottom 844 of the container 840. While not arequirement, having the container insert 820 in contact with the bottom844 of the container 840 can aid in stabilizing the insert within thecontainer 840. This may be important when accessing the container 840with a pipette tip, especially a pipette tip capable of facilitatinglevel sensing (e.g., capacitive level sensing) and a system configuredto initiate fluid aspiration at the pipette tip upon detected contact ofthe pipette tip with a fluid surface, as contact between the pipette tipand a misaligned insert could cause a pipettor of an associated analyzerto prematurely initiate an aspiration step. The irregular or undulatingbottom edge 830 of the container insert 820 prevents the bottom edge 830from forming a sealing contact with the bottom 844 of the container 840.The shape of the bottom edge 830 also creates one or more gaps 832between the bottom edge 830 of the container insert 820 and the bottom844 of the container 840 that promote filling and removal of the fluidcontents of the container 840.

The benefit of the insert 820 is that it limits the amount of a fluidsurface within the container 840 that is exposed to the atmosphere and,thus, reduces the amount of fluid evaporation when compared to thecontainer 840 without the insert 820. This is because only the fluidsurface within the tubular body 822 is exposed to atmosphere. As aresult, loss of fluid to evaporation loss is minimized, thereby makingmore of the fluid available for the intended use. Reducing evaporationalso increases the stability of the open container 840 on theinstrument.

While the container insert 820 is effective at retarding evaporation ofa liquid from the container 840, its presence can interfere with mixingof the fluid contents within the container 840. This is because fluidcontents within the container insert 820 can become isolated from fluidcontents outside the container insert 820. The holes 828 formed in thetubular body 822 of the container insert 820, however, are configured tofacilitate uniform mixing of fluid contents within the container insert820 by allowing fluid within the container 840 to flow between the spaceinside the tubular body 822 and the space outside the tubular body 822.Moreover, the one or more recesses 832 between the bottom edge 830 ofthe container insert 820 and the bottom 844 of the container 840 allowsfluid within the container 840 to mix and to enter the insert 820through the recesses 832.

Accordingly, the holes 828 and the recesses 832 help promote the mixingof the fluid contents of the container 840—either a fluid suspension ora fluid solution—by allowing migration of fluid between the space insidethe tubular body 822 and the area outside the tubular body 822, thusfacilitating an exchange of relatively un-mixed fluid contents insidethe tubular body 822 and relatively mixed fluid contents outside thetubular body 822. Proper mixing allows the particles of beads of a fluidsuspension to remain uniformly dispersed within the fluid contents ofthe container 840.

It is noted that while holes formed in a container insert help topromote mixing of fluid contents within the insert, the use of suchholes runs contrary to the purpose of the insert, which is to limitevaporation. As the fluid contents within a container fall below hole orset of holes, the fluid surface outside of the container insert becomesexposed to the atmosphere through the hole(s), and there is likely to beat least some evaporation through the exposed hole(s). Thus, theinventor discovered that an effective design of the container insertrequires a balancing of the somewhat contradictory requirements oflimiting fluid surface-atmosphere exposure on the one hand, andpromoting adequate mixing of the fluid within the insert by enablingfluid movement into and out of the insert on the other hand.

In various embodiments, a majority of the holes 828 are located on alower portion of the tubular body 822, meaning that all or most of theholes 828 are located below a midpoint of the length of the body 822, asshown in FIG. 14. While concentrating the holes 828 toward a lower endof the tubular body 822 may help reduce evaporation by delaying the timeat which the fluid level falls below the top hole(s) 828 and the fluidsurface outside of the container insert 820 becomes exposed to theatmosphere, extending the holes 828 toward the top of the body 822 mayhelp promote better mixing, allowing for more fluid movement into andout of the insert 820.

Thus, the size, number, and positions of the holes, while ideallyselected to limit evaporation, must be balanced with the need to provideadequate mixing. Mixing effectiveness may be empirically evaluated by,for example, taking optical density measurements with aliquots of thefluid contents taken from within and outside of a container insertfollowing agitation of a container. The optical density measurements ofthese aliquots will be similar if the solid supports are uniformlydistributed within the fluid contents.

An alternate embodiment of a container insert for reducing the amount ofevaporation from a container is indicated by reference number 850 inFIG. 16. The container insert 850 includes a tubular body 852 ofgenerally constant width with a plurality of holes 858 formed in a sidewall of the tubular body 852. In an exemplary embodiment, the tubularbody 852 is cylindrical and has a generally constant diameter from oneend thereof to an opposite end thereof. In an embodiment, the holes 858may be longitudinally aligned along the tubular body 852 and may beprovided on one or more sides of the tubular body 852. In variousembodiments, a majority of the holes 858 are located on a lower portionof the tubular body 852, meaning that all or most of the holes 858 arelocated below a midpoint of the length of the tubular body 852. Inanother embodiment, the holes 858 are distributed throughout the lengthof the body 852. In various embodiments, there are at least three holes858 on each of two opposed sides of the container insert 850, and theremay be 4, 5, 6 or more holes 858 on each of two opposed sides of theinsert 850 in such embodiments. In some embodiments, the containerinsert 850 includes a beveled surface 856 surrounding a top opening andan irregular or undulating bottom edge 860.

In various embodiments, an insert retainer feature of the containerinsert 850 includes a number of resilient tabs 854 (e.g., two or more)defined by angularly-spaced, axial slits 855 extending from a top edgeof the insert 850. The tabs 854 are splayed radially outwardly so thatthe outer dimension (e.g., diameter) of the tubular body 852 in thevicinity of the tabs 854 is larger than the outer dimension of theremainder of the tubular body 852. The outer dimension of the lower endof the tubular body 852 is preferably smaller than the inside dimensionof the container opening, so that the insert 850 is easily inserted intothe opening. The outer dimension of the tubular body 852 in the vicinityof the tabs 854, however, is larger than the inside dimension of thecontainer opening. The tabs 854 thus flex radially inwardly as thecontainer insert 850 is fully inserted into the container opening, andthe resilience of the tabs 854 creates a radial force between the tabs854 and the inside of the container opening, thereby securing the insert850 within the container.

In various embodiments, when the container insert 850 is fully insertedinto a container, the lower end of each slit 855 separating a pair oftabs 854 extends below the neck of the container, thereby creating asmall vent near the neck of the container to prevent a vacuum fromforming in the container. This feature is illustrated with the containerinsert 870 of FIG. 17.

As with container insert 820 described above and shown in FIGS. 14 and15, the holes 858 formed in the tubular body 852 of the insert 850 allowfluid within the container—including particles or beads in suspension—toflow between the space inside the tubular body 852 and the space outsidethe tubular body 852. Moreover, the undulating bottom edge 860 of thecontainer insert 850 creates one or more recesses between the bottomedge 860 of the insert 850 and the bottom of the container which allowsfluid within the container to mix and to enter the insert 850 throughthe recesses.

As noted above, a further alternate embodiment of a container insert forreducing the amount of evaporation from a container is indicated byreference number 870 in FIG. 17, which is a cross-sectional, perspectiveview of the container insert 870 inserted into a container 890. Thecontainer insert 870 includes a body 872 with a plurality of holes 878formed in a side wall of the body 872. In various embodiments, the body872 is tapered with a decreasing dimension, e.g., diameter if circularin cross-section, from the top of the body 872 toward the bottom of thebody 872.

The tapered shape of the embodiment of FIG. 17 is intended to generallyconform to the shape of a pipette tip. This design should further limitevaporation because as a fluid is withdrawn from the container 890 (andthe corresponding container insert 870), the fluid level drops and thesurface area of the fluid exposed to the atmosphere becomes increasinglysmaller. In some applications, however, the potential benefits oftapering to reduce evaporation must be balanced with the need to preventcontact between the container insert and a pipette tip inserted into thecontainer insert. If pipettor-based level sensing is employed, contactbetween the pipette tip and the container insert could signal anincorrect position of the fluid surface and an associated analyzer couldprematurely initiate an aspiration step before the pipette tip hasactually contacted the fluid surface.

In an embodiment, the holes 878 may be longitudinally aligned along thebody 872 and may be provided on one or more sides of the body 872. Invarious embodiments, a majority of the holes 878 are located in a lowerportion of the body 872, meaning that all or most holes 878 are locatedin a lower half of the body 872. In various embodiments, there are atleast three holes 878 on each of two opposed sides of the containerinsert 870, and there may be 4, 5, 6 or more holes 878 on each of twoopposed sides of the insert 870 in such embodiments. In someembodiments, the container insert 870 includes a beveled surface 876surrounding a top opening. In one or more embodiments, the containerinsert 870 includes one or more axial slots 880 extending from a bottomedge 882 of the body 872. In an embodiment, the container insert 870includes two diametrically-opposed axial slots 880. As an alternative tothe axial slots 880, the container insert 870 may have an irregular orundulating bottom edge.

In an exemplary embodiment, the container insert 870 includes, above thebody 872, an upper portion 873 of a transverse dimension, e.g., adiameter that is larger than a transverse dimension of the body 872 anda tapered transition 874 between the upper portion 873 and the body 872.

The container insert 870 is inserted into the container 890 through anopening at the top of a neck 892 of the container 890. As shown in FIG.17, the length of the container insert 870 may be such that a top end ofthe insert 870 is disposed at or just below the top of the containerneck 892 and the bottom edge 882 of the insert 870 is in contact withthe bottom 894 of the container 890. The axial slot(s) 880 of thecontainer insert 870 prevent the bottom edge 882 from forming a sealingcontact with the bottom 894 of the container 890.

In various embodiments, an insert retainer feature of the containerinsert 870 includes a number of resilient tabs 877 (e.g., two or more)defined by angularly-spaced, axial slits 875 extending from a top edgeof the insert 870. The tabs 877 may be splayed radially outwardly—whenthe container insert 870 is not installed in a container—so that theouter width (e.g., diameter) of the upper portion 873 in the vicinity ofthe tabs 877 is larger than the inside width of the container opening.The tabs 877 thus flex radially inwardly as the container insert 870 isfully inserted into the container opening, and the resilience of thetabs 877 generates a radial force between the tabs 877 and the inside ofthe container opening, thereby securing the insert 870 within thecontainer 890.

In various embodiments, when the container insert 870 is fully insertedinto a container 890, the lower end of each slit 875 separating a pairof tabs 877 extends below the neck 892 of the container 890, therebycreating a small vent 879 near the neck of the container to prevent avacuum from forming in the container and to permit air to escape fromthe container 890 during fluid fill.

As with container inserts 820 and 850 described above, the holes 878formed in the body 872 of the insert 870 allow fluid within thecontainer—including particles or beads in suspension—to flow between thespace inside the body 872 and the space outside the body 872. Moreover,the slot(s) 880 allow fluid within the container 890 to mix and to enterthe container insert 870 through the slot(s) 880. The size and number ofslot(s) 880 at the base of the insert are chosen to facilitate fluidflow into and out of the body 872 and removal of fluid from thecontainer by a fluid transfer apparatus, such as a robotic pipettor,inserted into the body 872. In one embodiment, the slot(s) areapproximately 5/16 inches in length. These slot(s) may be flared out asshown, meaning that the slot is wider at one end—e.g., the lowerend—than at an opposite end—e.g., the top end.

The material selected for the container insert should not leach whencontacted with the fluid to be contained. In various embodiments, thecontainer insert is injection molded with the same material used to formthe container (e.g., polyethylene or polypropylene).

Comparative Data

Representative data indicative of the efficacy of a fluid containermixing device embodying aspects of the present disclosure is shown inTABLE 1 below.

TABLE 1 Absorption (600 nm) % of Panther AC2 AC2 250TK mixed on Panther0.3312 100.0% AC2 250TK 3.75 Hz 20 sec 0.320 96.5% AC2 250TK 3.75 Hz 10min 0.336 101.3% AC2 100TK 3.75 Hz 10 min 0.335 101.2% Ultrio Ultriomixed on Panther 0.5132 100.0% Ultrio 3.75 Hz 20 sec 0.505 98.4% Ultrio3.75 Hz 10 min 0.513 100.0% Each AC2 sample contains 100 μL TCR and 900μL swab transport medium (“STM”) Each Ultrio sample contains 400 μL TCRand 600 μL STM

In TABLE 1, mixing data for two different types of target capturereagent (“TCR”), “AC2” and “Ultrio”, is shown for differently-sizedcontainers and different mixing conditions.

Since light passed through a fluid is partially absorbed by particlessuspended in the fluid, the more particles that are suspended in thefluid the more light that is absorbed. Thus, the level of lightabsorption is an indication of the amount of particles suspended in thefluid and thus how “mixed-up” the fluid is. Thus, mixing efficacy isinferred, in the data presented in TABLE 1, from the level of absorptionof 600 nm light passed through an aliquot of fluid taken from near thetop of the fluid surface within the container and measured with aspectrophotometer. The amount of mixing—as inferred from the amount ofabsorption—achieved by a fluid container mixing device embodying aspectsof the present disclosure is compared against the amount of mixingachieved by the TCR mixer employed in the “PANTHER” molecular diagnosticsystem available from Hologic, Inc. (see U.S. Pat. No. 7,135,145 “Devicefor agitating the fluid contents of a container”).

For the AC2 TCR, mixing achieved in differently-sized containers—250test kit (“TK”) medium container or 100 TK small container—mixed at 3.75Hz for 20 seconds or 10 minutes was compared to mixing achieved in a 250TK container mixed on the PANTHER TCR mixer. The mixing achieved by thePANTHER TCR mixer resulted in a level of absorption of 0.3312. Themixing achieved by the mixing device of the present disclosure resultedin a level of absorption of 0.320 when a 250 TK container was mixed for20 seconds, 0.336 when a 250 TK container was mixed for 10 minutes, and0.335 when a 100 TK container was mixed for 10 minutes. Thus, after 20seconds, the mixing device of the present disclosure achieved 96.5% ofthe level of mixing that was achieved by the PANTHER TCR mixer, andafter 10 minutes, the mixing device of the present disclosure achievedmore than 101% of the level of mixing that was achieved by the PANTHERTCR mixer.

For the Ultrio TCR, mixing achieved in a large container at 3.75 Hz for20 seconds or 10 minutes was compared to mixing achieved by the PANTHERTCR mixer. The mixing achieved by the PANTHER TCR mixer resulted in alevel of absorption of 0.5132. The mixing achieved by the mixing deviceof the present disclosure resulted in a level of absorption of 0.505when the suspension was mixed for 20 seconds and 0.513 when thesuspension was mixed for 10 minutes. Thus, after 20 seconds, the mixingdevice of the present disclosure achieved 98.4% of the level of mixingthat was achieved by the PANTHER TCR mixer, and after 10 minutes, themixing device of the present disclosure achieved 100% of the level ofmixing that was achieved by the PANTHER TCR mixer.

Thus, the data of TABLE 1 demonstrates that a fluid container mixingdevice embodying aspects of the present disclosure achieves a level ofmixing that is as good as or better than the level of mixing achieved bythe PANTHER TCR mixer.

Hardware and Software

Aspects of the disclosure are implemented via control and computinghardware components, user-created software, data input components, anddata output components. Hardware components include computing andcontrol modules (e.g., system controller(s)), such as microprocessorsand computers, configured to effect computational and/or control stepsby receiving one or more input values, executing one or more algorithmsstored on non-transitory machine-readable media (e.g., software) thatprovide instruction for manipulating or otherwise acting on the inputvalues, and output one or more output values. Such outputs may bedisplayed or otherwise indicated to a user for providing information tothe user, for example information as to the status of the instrument ora process being performed thereby, or such outputs may comprise inputsto other processes and/or control algorithms. Data input componentscomprise elements by which data is input for use by the control andcomputing hardware components. Such data inputs may comprise positionssensors, motor encoders, as well as manual input elements, such askeyboards, touch screens, microphones, switches, manually-operatedscanners, etc. Data output components may comprise hard drives or otherstorage media, monitors, printers, indicator lights, or audible signalelements (e.g., buzzer, horn, bell, etc.).

Software comprises instructions stored on non-transitorycomputer-readable media which, when executed by the control andcomputing hardware, cause the control and computing hardware to performone or more automated or semi-automated processes.

While the apparatus has been described and shown in considerable detailwith reference to certain illustrative embodiments, including variouscombinations and sub-combinations of features, those skilled in the artwill readily appreciate other embodiments and variations andmodifications thereof as encompassed within the scope of the presentdisclosure. Moreover, the descriptions of such embodiments,combinations, and sub-combinations is not intended to convey that theapparatus requires features or combinations of features other than thoseexpressly recited in the claims. Accordingly, the disclosure is deemedto include all modifications and variations encompassed within thespirit and scope of the following appended claims.

1. A method for removing fluid contents of a container while minimizingevaporation of the fluid contents from the container, the methodcomprising: a) inserting an evaporation-limiting insert into an openingof a neck of the container, the evaporation-limiting insert comprising ahollow tubular body configured to extend into the container from theneck of the container, the tubular body including a plurality of holesformed through a wall of the tubular body and distributed along at leasta portion of the length of the tubular body, and b) after step a),inserting a portion of a fluid transfer apparatus through the opening ofthe container and into the tubular body of the evaporation-limiting andwithdrawing a portion of the fluid contents from the container with thefluid transfer apparatus.
 2. The method of claim 1, wherein the fluidtransfer apparatus comprises a robotic pipettor, and step b) comprisesinserting a pipette tip associated with the robotic pipettor through theopening of the container and into the tubular body of theevaporation-limiting insert and aspirating a portion of the fluidcontents from the container with the robotic pipettor.
 3. The method ofclaim 2, further comprising performing liquid level sensing with therobotic pipettor.
 4. The method of claim 1, further comprising, prior tostep b), the step of agitating the fluid contents of the container topromote mixing of the fluid contents, whereby the holes formed throughthe wall of the tubular body of the insert permit fluid to flow througha space inside the tubular body.
 5. The method of claim 4, wherein thefluid contents comprise solid supports, wherein each of the holes issized to permit passage of the solid supports therethrough, and whereinthe agitating step is performed to keep the solid supports insuspension.
 6. The method of claim 4, wherein agitating the fluidcontents of the container comprises agitating the container.
 7. Themethod of claim 1, wherein the surface of the fluid contents within thecontainer is above the top-most one of the holes formed through the wallof the tubular body.
 8. The method of claim 1, further comprising thestep of determining the height of the fluid contents within thecontainer with an apparatus configured to detect a fluid surfaceinserted through the opening of the container and into the tubular bodyof the evaporation-limiting insert.
 9. The method of claim 1, wherein amajority of the holes are located on a lower portion of the tubularbody, and the fluid contents comprise solid supports, and wherein eachof the holes is sized to permit passage of the solid supportstherethrough, and further comprising the step of agitating the fluidcontents of the container to keep the solid supports in suspension. 10.The method of claim 9, wherein the solid supports aremagnetically-responsive particles or beads.
 11. The method of claim 1,wherein the tubular body has a length extending from the opening of thecontainer to a bottom surface of the interior of the container.
 12. Themethod of claim 11, wherein the tubular body has a bottom edgeconfigured to form one or more gaps between the bottom edge and thebottom surface of the container.
 13. The method of claim 11, wherein thetubular body of the evaporation-limiting insert comprises one or moreslots extending axially from the bottom edge to thereby form one or moregaps between the bottom edge and the bottom surface of the container.14. The method of claim 1, wherein the evaporation-limiting insertfurther comprises a retainer feature at an upper end portion of thetubular body that is configured to engage an inner portion of the neckof the container to secure the insert within the container.
 15. Themethod of claim 14, wherein the retainer feature comprises a detentengaged with an inside surface of the container.
 16. The method of claim14, wherein the retainer feature comprises two or more outwardly splayedresilient tabs formed at a top portion of the tubular body and pressingresiliently against an inside surface of the container.
 17. The methodof claim 16, wherein the tabs are separated by slits extendinglengthwise in a wall of the tubular body from a top edge thereof,wherein the length of each slit is longer than the neck of thecontainer, so that the slit extends below the neck of the container. 18.The method of claim 1, wherein the holes through theevaporation-limiting insert are axially aligned along a side of thetubular body.
 19. The method of claim 1, wherein the holes are arrangedin two groups axially aligned along opposed sides of the tubular body.20. The method of claim 19, wherein each group of axially aligned holescomprises at least three holes.
 21. The method of claim 20, wherein eachgroup of axially aligned holes comprises no more than six holes.
 22. Themethod of claim 1, wherein the tubular body is substantially cylindricaland has a substantially constant diameter along its entire length. 23.The method of claim 1, wherein the tubular body is tapered such that anoutside dimension of the tubular body progressively decreases movingaway from the opening of the container.
 24. The method of claim 1,wherein all of the holes are situated below the midpoint of the tubularbody.